The Washington Post reported that de Filippis was arrested at 6:40am on 28 November and detained until about 11.30am as part of the police investigation into a two-year-old defamation case.

De Filippis wrote that he was manhandled, handcuffed, humiliated in front of his sons, twice forced to strip and submit to body cavity searches and interrogated without lawyers by an investigating magistrate.

The case prompted an outcry among journalists, lawyers, politicians and others, who condemned the police behaviour as out of place in a country with traditions of the rule of law and freedom of expression.

President Sarkozy has now issued a statement calling for the penal code to be revised so as to decriminalise defamation – a criminal offence in France, punishable only by a fine.

He also called for a new amendment to criminal procedures to make them more human and transparent.

The newspaper Le Monde reported that Sarkozy’s call for reform ran counter to his own government’s approach to law and order.

Media rights group Reporters Without Borders condemned the “coercive methods” the police and court had used, saying they were a sign of “deterioration in press freedom in France”.

“We are outraged by the unacceptable methods used against Vittorio de Filippis and their humiliating nature,” the group said in a statement.

“Such a thing has never before been heard of in France. To treat a journalist like a criminal and resort to practices such as body searches is not only shocking but unworthy of French justice.”

The investigating magistrate, Muriel Josie, refused to explain what had happened.

Police also refused to comment – but the Agence France-Presse news agency quoted police sources as saying that de Filippis was hauled in because he had not responded to a posted summons and that he had suffered rough treatment because he talked back to the “irreproachable” officers who arrived at his door.